Corsair SF1000L SFX-L Power Supply Review

1. Introduction 2. Bundle & Cabling 3. External 4. Internal 5. Testing Methodology and Results 6. Closing Thoughts 7. View All Pages

There have been quite a few high quality power supplies released in the last month and today we take a look at another new one from Corsair, the SF1000L. This is a fully modular SFX-L form factor unit, offering 80 Plus Gold Certification and high levels of build quality across the board.

Right now this power supply is available from Overclockers UK For £219.95 inc vat ( HERE ). While we will take a closer look when we open the unit later in the review, Corsair are keen to point out that the adoption of Japanese capacitors and low noise PWM fan ensures long life and reliability, they are also backing this unit up with a 7 year warranty. Not quite at the highest levels we see from other manufacturers such as Seasonic (12 years), but it should provide coverage for two to three system upgrades.

• Compact SFX-L Form-Factor PSU: Delivers 850/1000W of continuous power, ideal for power-dense small-form- factor PCs, or saving space in larger builds.
• Fully Modular, Micro-Fit Type-5 PSU Connectors: With flexible cabling, taking up less space for tidy cable management and compatibility in small cases.
• Intel® ATX 3.0 Certified: Compliant with the ATX 3.0 power standard, supporting the PCIe Gen 5 platform and resisting transient power spikes.
• 120mm Rifle Bearing PWM Fan: Delivers quiet, powerful cooling, with Zero RPM fan mode for near-silent operation at lower loads.
• 80 PLUS Gold-Certified: Operates at up to 90% efficiency, and Cybenetics-certified for lower power consumption, less noise, and cooler temperatures.
• 100% Japanese 105°C-Rated Electrolytic Capacitors: Ensure unwavering power and reliability.
• Modern Standby Support: Unlocks extremely fast wake-from-sleep times and better low-load efficiency.
• 40°C Maximum Operating Temperature: For reliable power even under high-stress conditions.
• Resonant LLC Topology: Provides clean, consistent power and enables use of more energy-efficient sleep states.
• 10. Seven-Year Warranty: For complete peace of mind.

Corsair are following their tried and true marketing colour scheme for this unit – bright yellow artwork and a high resolution image of the power supply on the front of the box.

The rear of the box showcases some technical data on the power supply, along with some images of the modular bay and dimensions of the unit.

Inside the box is a bunch of modular cables, along with the power supply protected between foam. A mounting bracket and some cable ties are also included.

Corsair are including two EPS connectors on separate cables as well as three PCIe 6+2pin individual cables. There is also a single 12VHPWR cable at 600W. Corsair also bundle in three 4-pin Molex cables as well and eight SATA cables. The cables are relatively short which ties in perfectly fine with the smaller SFX-L form factor.

The SF1000L SFX-L is a very understated unit, finished in neutral grays and blacks to suit a variety of themed system builds. The power supply is compact, measuring 130mm x 125mm x 63.5mm.

A large fan is hidden behind a grille. We will get a closer look at this when we crack the unit open shortly.

The modular bay is well laid out and labelled for ease of use during the build phase. The other side of the unit is home to the power switch and socket, alongside another vented panel to aid with airflow.

The power supply can deliver 20A on both +3.3V and +5V. It can deliver 83.3A over the +12V rail which is plenty of power for high end graphics cards.

Corsair are using an NR1215 fan, 120mm, 0.55A. This fan is fluid dynamic bearing (FDB), and technically reliable over long periods of time.

This looks to be a Great Wall OEM design in partnership with Corsair. They are a company with a pretty rich back history in designing solid SFX platform power supplies. A large centralised heatsink is positioned to help remove excess heat from the PCB and components around it. The design incorporates both VRMs on a PCB. The primary stage incorporates two Japanese Rubycon electrolytic capacitors rated 105C. These caps are rated 420V 330uF and 510uF for a total of 840uF.

Great Wall soldering standards on this board are really very good overall. This supply offers OVP, OCP, SCP, OPP and OTP protections.

Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 watt DC load.

We test ambient temperatures at 35c in our environment to greater reflect warmer internal chassis conditions.

We use combinations of the following hardware:
• SunMoon SM-268
• CSI3710A Programmable DC load (+3.3V and +5V outputs)
• CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa)
• Digital oscilloscope (20M S/s with 12 Bit ADC)

• Variable Autotransformer, 1.4 KVA

We test in a single +12V configuration.

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
100W	0.90	3.34	0.90	5.02	7.35	12.08	0.50	5.01	0.20	-12.01
200W	1.60	3.34	1.64	5.02	15.13	12.08	1.00	5.01	0.20	-12.02
500W	3.21	3.34	3.24	5.03	38.60	12.07	1.50	5.01	0.20	-12.02
750W	4.03	3.34	4.17	5.02	58.53	12.05	2.00	5.00	0.30	-12.01
1000W	5.45	3.34	5.51	5.02	78.13	12.04	2.50	5.01	0.30	-12.01

The load regulation of this power supply is very tight throughout.

Corsair SF1000L	Maximum Load
	1110W

The power supply managed to deliver 1110W before shutting down safely.

Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.

Cross Load Testing	+3.3V		+5V		+12V		-12V		+5VSB
	A	V	A	V	A	V	A	V	A	V
885W	2.0	3.34	2.0	5.02	72.0	12.04	0.2	-12.01	0.50	5.00
240W	20.0	3.33	23.0	5.00	2.0	12.08	0.2	-12.01	0.50	5.01

The Corsair SF1000L handled our cross load test very well, holding stable results across the range.

We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum. ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.

ATX12V Ver 2.2 Noise/Ripple Tolerance
Output	Ripple (mV p-p)
+3.3V	50
+5V	50
+12V1	120
+12V2	120
-12V	120
+5VSB	50

Obviously when measuring AC noise and ripple on the DC outputs, the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
100W	5	5	5	5
250W	5	10	10	5
500W	5	10	10	5
750W	10	15	15	10
1000W	10	15	20	10

Ripple noise suppression is really good on the primary and minor rails, falling well within industry rated parameters.

Efficiency (%)
100W	88.8
250W	90.1
500W	92.5
750W	91.6
1000W	89.4

The efficiency results are excellent, peaking at 92.5% at close to 55% load. This drops to just under 90% efficiency at full load. These are really very positive results for an 80 Plus Gold rated unit.

We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.

Today to test the Power Supply we have taken it into our acoustics room environment and have set our SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa) one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.

As this can be a little confusing for people, here are various dBa ratings in with real world situations to help describe the various levels.

KitGuru noise guide

10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refrigerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum

Noise (dBA)
100W	<28.0
250W	<28.0
500W	31.8
750W	33.6
1000W	38.3

Corsair seem to have set this fan up to be very aggressive when the load ramps up after 700 Watts. It becomes quite audible fairly quickly after 500 Watts and at full load is somewhat annoying, even in a room with a few systems in operation. If you are particularly susceptible to raised noise levels then we would recommend you think twice about purchasing this unit.

Temperature (c)
	Intake	Exhaust
100W	37	42
250W	38	46
500W	40	55
750W	45	54
1000W	46	60

The large fan spins quite fast at higher loads which ensures that temperatures are never an issue. While this is great, I would have preferred if Corsair had optimised this a little better to be perfectly honest. A more balanced fan curve would have worked better overall in my opinion.

Maximum load	Efficiency
1110W	88.5

Pushing the PSU well above its rated limits generates an efficiency of around 88.5. Not really practical, but interesting nonetheless.

There is no doubt that Corsair's partnership with Great Wall has delivered some great power supplies in the past, and the SF1000L SFX-L continues that trend. Overall performance levels from this power supply are excellent with no real discernible weaknesses we can note. This unit is capable of handling a smaller form factor gaming system utilising a high power draw RTX 4090 graphics card.

My main issue with this power supply is the noise generated once loads hits 600 Watts and higher. At around 750 Watts, I found the noise output to be slightly distracting, and at over 900 Watts the unit was clearly audible above several systems running in the same room. You could argue that for a smaller form factor gaming system this added airflow would be beneficial long term but, for me personally, I would struggle to deal with the noise output if the power demand was more than 600 Watts. I feel Corsair and Great Wall could have optimised the noise output to airflow ratio a little better.

Pricing for a supply in this category is very fair, and technically you would be confident that the unit will deliver high levels of clean power long term. Corsair have adopted high grade Japanese 105C rated capacitors in the primary stage, and noise suppression is stellar. Load regulation was also rock solid throughout our testing.

You can buy the Corsair SF1000L SFX-L from Overclockers UK for £219.95 HERE .

Pros:

• Reasonable pricing for an SFX-L unit.
• Load regulation is tight.
• High levels of build quality.
• Efficient for a 80 Plus Gold unit.
• Fully modular.
• Fluid dynamic bearing fan should last.
• Seven year warranty.

Cons:

• Loud under moderate and higher loads.

KitGuru says: If you don't mind some extra noise under load, the Corsair SF1000L SF-L delivers exceptionally high quality power right up to the rated 1000 Watts. The adoption of quality 105C Japanese Rubycon capacitors in the primary stage and 7 year warranty will surely give peace of mind for anyone in the market for a new power supply.

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